1. Field of the Invention
The present invention relates to a manufacturing system in which articles are manufactured by a manufacturing facility, e.g., a manufacturing line or manufacturing cell including a plurality of manufacturing devices.
2. Description of the Related Art
Manufacturing facilities, e.g., manufacturing lines or manufacturing cells, are installed in factories. Such manufacturing facilities include a plurality of manufacturing devices that perform manufacturing processes such as machining and assembly. Parts are transferred into the manufacturing devices in a predetermined order so as to be machined and assembled, achieving uniformly manufactured articles.
In the related art, in order to manufacture uniform articles with a high yield in such a manufacturing facility, a plurality of identical manufacturing devices, e.g., machining devices configured to perform the same machining or assembling devices configured to perform the same assembly, may be disposed for the respective manufacturing processes. Specifically, when an article is obtained through a machining process and an assembling process, one of the identical machining devices can be selectively used in the machining process, whereas one of the identical assembling devices can be selectively used in the assembling process.
However, even if the quality (e.g., dimensional accuracy) of parts manufactured by the identical manufacturing devices satisfies requirement specifications, actually manufactured parts vary in quality among the manufacturing devices because of a bias of each of the manufacturing devices. Thus, ultimately obtained articles also vary in quality depending on a combination of the manufacturing devices used or the combination of manufactured parts.
It is desirable that such variations in quality are minimized to improve the quality of articles. However, strict requirement specifications set for the individual manufacturing devices and manufactured parts may increase cost.
Techniques for improving the quality of articles are described in, for example, Japanese Patent No. 4239932 and Japanese Patent No. 5540659.
Japanese Patent No. 4239932 describes a production management system that automatically specifies a process as a fundamental cause of variations in the quality of articles when an abnormality is found in the quality of articles in a manufacturing line for manufacturing articles through a plurality of manufacturing processes, and at least one inspection process.
Japanese Patent No. 5540659 describes a process planning apparatus that provides production planning for a manufacturing line for manufacturing articles through a plurality of manufacturing processes, each including selectable manufacturing devices. The process planning apparatus is configured such that a combination of manufacturing devices meeting quality standards is selected using a mean value of quality information for each process route and a standard deviation, and production planning for specifying a process route is then determined and presented to the outside based on the selected combination of manufacturing devices.